Quit with an error status on SIGTERM during migration

This prevents the supervisor from thinking that the migration completed
successfully.

In order to do this, I've introduced a new lock around the start (and
finish) of the migration so that we avoid a race between the signal
handler in the server_accept loop and the control thread mirror startup.
Without that, we'd risk successfully starting a migration after the
SIGTERM handler fired, which would be Bad.

tests/acceptance/environment.rb

@@ -121,11 +121,12 @@ class Environment
 
   def run_fake( name, addr, port, sock=nil )
     fakedir = File.join( File.dirname( __FILE__ ), "fakes" )
-    fake = Dir[File.join( fakedir, name ) + "*"].sort.find { |fn|
+    fakeglob = File.join( fakedir, name ) + "*"
+    fake = Dir[fakeglob].sort.find { |fn|
       File.executable?( fn )
     }
 
-    raise "no fake executable" unless fake
+    raise "no fake executable at #{fakeglob}" unless fake
     raise "no addr" unless addr
     raise "no port" unless port
 

tests/acceptance/fakes/dest/sigterm_after_hello.rb

@@ -0,0 +1,19 @@
+#!/usr/bin/env ruby
+
+# Wait for a sender connection, send a correct hello, then sigterm the
+# sender.  We expect the sender to exit with status of 6, which is
+# enforced in the test.
+
+require 'flexnbd/fake_dest'
+include FlexNBD
+
+addr, port, pid = *ARGV
+server = FakeDest.new( addr, port )
+client = server.accept( "Timed out waiting for a connection" )
+client.write_hello
+
+Process.kill(15, pid.to_i)
+
+client.close
+server.close
+exit 0

tests/acceptance/fakes/source/sigterm_after_hello.rb

@@ -0,0 +1,20 @@
+#!/usr/bin/env ruby
+
+# Connect to the listener, wait for the hello, then sigterm the
+# listener.  We expect the listener to exit with a status of 6, which
+# is enforced in the test.
+
+require 'flexnbd/fake_source'
+include FlexNBD
+
+addr, port, pid = *ARGV
+
+client = FakeSource.new( addr, port, "Timed out connecting." )
+client.read_hello
+
+Process.kill( "TERM", pid.to_i )
+
+sleep(0.2)
+client.close
+
+exit(0)

tests/acceptance/flexnbd.rb

@@ -136,11 +136,11 @@ class ValgrindKillingExecutor
 
 
   def call( err )
-    Process.kill( "KILL", @pid )
     $stderr.puts "*"*72
     $stderr.puts "* Valgrind error spotted:"
     $stderr.puts err.to_s.split("\n").map{|s| "  #{s}"}
     $stderr.puts "*"*72
+    Process.kill( "KILL", @pid )
     exit(1)
   end
 
@@ -323,7 +323,8 @@ module FlexNBD
 
 
     def serve( file, *acl)
-      run_serve_cmd( serve_cmd( file, acl ) )
+      cmd = serve_cmd( file, acl )
+      run_serve_cmd( cmd )
     end
 
     def listen(file, *acl)

tests/acceptance/test_dest_error_handling.rb

@@ -28,6 +28,11 @@ class TestDestErrorHandling  < Test::Unit::TestCase
   end
 
 
+  def test_sigterm_has_bad_exit_status
+    @env.nbd1.can_die(1)
+    run_fake( "source/sigterm_after_hello" )
+  end
+
   def test_disconnect_after_hello_causes_error_not_fatal
     run_fake( "source/close_after_hello" )
     assert_no_control

tests/acceptance/test_source_error_handling.rb

@@ -19,12 +19,24 @@ class TestSourceErrorHandling < Test::Unit::TestCase
   end
 
 
+  def expect_term_during_migration
+    @env.nbd1.can_die(6,9)
+  end
+
+
   def test_failure_to_connect_reported_in_mirror_cmd_response
     stdout, stderr = @env.mirror12_unchecked
+    expect_term_during_migration
     assert_match( /failed to connect/, stderr )
   end
 
 
+  def test_sigterm_after_hello_quits_with_status_of_1
+    expect_term_during_migration
+    run_fake( "dest/sigterm_after_hello" )
+  end
+
+
   def test_destination_hangs_after_connect_reports_error_at_source
     run_fake( "dest/hang_after_connect",
               :err => /Remote server failed to respond/ )
@@ -36,6 +48,7 @@ class TestSourceErrorHandling < Test::Unit::TestCase
               :err => /Mirror was rejected/ )
   end
 
+
   def test_wrong_size_causes_disconnect
     run_fake( "dest/hello_wrong_size",
               :err => /Remote size does not match local size/ )
@@ -43,38 +56,45 @@ class TestSourceErrorHandling < Test::Unit::TestCase
 
 
   def test_wrong_magic_causes_disconnect
+    expect_term_during_migration
     run_fake( "dest/hello_wrong_magic",
               :err => /Mirror was rejected/ )
   end
 
 
   def test_disconnect_after_hello_causes_retry
+    expect_term_during_migration
     run_fake( "dest/close_after_hello",
               :out => /Mirror started/ )
   end
 
 
   def test_write_times_out_causes_retry
+    expect_term_during_migration
     run_fake( "dest/hang_after_write" )
   end
 
 
   def test_rejected_write_causes_retry
+    expect_term_during_migration
     run_fake( "dest/error_on_write" )
   end
 
 
   def test_disconnect_before_write_reply_causes_retry
+    expect_term_during_migration
     run_fake( "dest/close_after_write" )
   end
 
 
   def test_bad_write_reply_causes_retry
+    expect_term_during_migration
     run_fake( "dest/write_wrong_magic" )
   end
 
 
   def test_pre_entrust_disconnect_causes_retry
+    expect_term_during_migration
     run_fake( "dest/close_after_writes" )
   end